Partial Discharge Characteristics of Aviation Cables Under Composite Voltages

With the urgent demand for high power in the electrical systems for more-electric aircraft (MEA), high-voltage direct current has emerged as the primary strategy for energy supply. However, the excitation of partial discharge (PD) activities under dc voltage is challenging and unexcepted. AC–DC composite waveforms are proposed as the high-voltage source to observe and evaluate the PD in this article. The specific range of composite ratios, mainly including the frequency of the introduced ac component and their voltage amplitudes, are explored under ac–dc composite voltages. An equivalent coefficient on the basis of cumulative discharge amplitude is put forward to quantitatively assess the similarity between PD under dc and ac–dc composite voltages. It is indicated that the recombination ratio falls within the range of 8%–18% and the frequency of the ac component ranges from 50 Hz to 1 kHz is recommended to get an effective replacement for PD detection. It provides an alternative approach to get access to PD profiling for high-voltage dc aviation cables in specific MEA scenario, enabling a lower and safer excitation voltage to evaluate the insulation performances.